The present invention relates to a method for lead introduction and fixation and, more particularly, to a method for the introduction and fixation of a neural stimulator lead in the epidural space of the spinal cord of a patient.
Neural stimulator electrodes and leads have been employed in the past which have been implanted in the epidural space of the spinal cord of a patient for stimulating selected locations along the spinal cord for such purposes as the relief of pain. One method of introduction and implantation is disclosed in U.S. Pat. No. 4,285,347. In that patent a neural stimulator lead is disclosed in which the leading distal end of the lead is axially moved along the epidural space in the spinal cord by passing the end through a Tuohy needle and pushing the end of the lead to the location on the dura where it is to stimulate the spinal cord. The lead disclosed in that patent has a configuration at its distal end and adjacent the stimulating electrode which may be deformed during installation of the lead by a stylet which passes through the lead to minimize the pain and trauma to the patient. Once the lead has been positioned as desired, the stylet is removed to cause the distal end of the lead to expand to minimize subsequent axial or lateral movement of the lead once it has been placed.
The method of introduction and fixation incorporating the principles of the present invention realizes several advantages over the prior methods of placement and fixation of neural stimulator leads. A method incorporating the principles of the present invention greatly facilitates the positioning of the lead electrodes with a minimum of effort and a minimum of trauma to the patient and essentially precludes the need for repositioning of the lead once it has been positioned. A method incorporating the principles of the present invention enables fixation of the lead at two points, thus minimizing the possibility of axial or lateral movement of the lead once it has been installed. A method incorporating the principles of the present invention may also eliminate the need for the use of a stylet during installation, thereby minimizing pain and trauma to the patient which might be associated with the installation and fixation procedure. A method incorporating the principles of the present invention enables precise control of the lead during installation and fixation by providing for manipulation simultaneously of both ends of the lead.
In one principal aspect of the present invention, a method of introduction of a percutaneous conductive lead in the body of a patient for implantation of the lead therein includes inserting first and second hollow needles through the skin of the patient to a subcutaneous depth at which the lead is to be fixed. The tips of the needles are spaced from each other on opposite sides of the location which is to be stimulated by the lead and the tips of the needles are positioned to face each other. A lead is inserted through the first hollow needle and the lead is passed through the patient's body until its leading distal end is adjacent the tip of the second needle. A snare is inserted through the second needle and the leading distal end of the last mentioned lead is snared and pulled through the second hollow needle so that the last mentioned lead extends from the patient's body through both of the hollow needles.
In another principal aspect of the present invention, the last mentioned lead is a surrogate lead. After the surrogate lead has been snared and pulled through the second needle, one of the ends of the surrogate lead is attached to the conductive lead and the conductive lead is pulled completely through one of the needles at least to the tip of the other needle, and the attached end of the conductive lead is further pulled such that both ends of the conductive lead extend from the patient's body.
In still another principal aspect of the present invention, the conductive lead is a neural stimulator lead for stimulating the spinal cord of a patient and the needles and the conductive lead are inserted into the epidural space of the patient's spinal canal.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.